1. Field of the Invention
The present invention generally relates to a pixel array substrate and a liquid crystal display (LCD), and more particularly, to a multi-domain vertically alignment pixel array substrate (MVA pixel array substrate) and an LCD.
2. Description of Related Art
The rapid progress in terms of multimedia today benefits greatly from the developments in semiconductor devices and displays. Among various displays, the thin film transistor liquid crystal display (TFT LCD) has played a major role on the mainstream display market due to advantages of high display quality, high space utilization, low power consumption and no radiation.
Currently, the performance demand on an LCD from the consumable market focuses on high contrast ratio, no gray scale inversion, low color shift, high luminance, high chroma, high color saturation, rapid response and wide viewing angle. The LCDs qualified for the wide viewing angle requirement at present include twisted nematic liquid crystal display (TN-LCD) with wide viewing films, in-plane switching liquid crystal display (IPS-LCD), fringe field switching liquid crystal display (FFS-LCD) and multi-domain vertically alignment liquid crystal display (MVA-LCD).
The related art of a conventional MVA-LCD is briefly described as follows. FIG. 1 is a top view diagram of a pixel array substrate within a single pixel region in a conventional MVA-LCD. Referring to FIG. 1, in a conventional MVA-LCD, a scan line 102 and a data line 104 are disposed on a pixel array substrate 100, wherein the scan line 102 and the data line 104 together define a pixel region. A first active device 106, a second active device 108 and a pixel electrode 110 are disposed within the single pixel region of the pixel array substrate 100. The first active device 106 and the second active device 108 are respectively electrically connected to the scan line 102 and the data line 104. The pixel electrode 110 has a plurality of alignment slits 112 and a plurality of fine slits 114. In addition, in order to promote the display effect of an MVA LCD panel, the alignment slits 112 are used to partition the pixel electrode 110 into a first pixel electrode 110A and a second pixel electrode 110B separated from each other. The first pixel electrode 110A and the second pixel electrode 110B are respectively electrically connected to the first active device 106 and the second active device 108.
The pixel array substrate 100 is assembled with a color filter substrate (CF substrate) (not shown) having a plurality of slits, and the gap between the pixel array substrate 100 and the CF substrate (not shown) is filled with liquid crystal to form an LCD. After turning on the LCD, the slits (112 and 114) disposed on the pixel array substrate 100 or those disposed on the CF substrate (not shown) are conducive to generate a fringe field effect and the electric field lines at the slits exhibit curved paths. Therefore, the fringe field effect can be utilized to make the liquid crystal molecules arrange in multiple directions so as to obtain several different alignment domains. An MVA-LCD takes advantage of the above-mentioned characteristic to satisfy the wide viewing angle requirement. In addition, while an MVA-LCD is displaying, the first pixel electrode 110A and the second pixel electrode 110B can have different voltages, thereby potentially improving possible problems of color shift when viewing a display frame by a viewer from a large viewing angle.
However, in order to realize the layout of pixel electrode 110 as shown by FIG. 1, the second pixel electrode 110B must typically have a plurality of thin connection portions 116 to interconnect a plurality of electrode patterns at different positions, wherein the length of connection portions 116 can be tens of microns. Unfortunately, if even a minor process error occurs during fabrication of the pixel electrode 110, the connection portions 116 may exhibit broken-line defects. Moreover, once a connection portion 116 has a broken-line defect, the second pixel electrode 110B would be split into two independent electrode patterns, and one of the two independent electrode patterns of the second pixel electrode 110B fails to receive the voltage signal delivered by the second active device 108 for displaying. In other words, a minor process error may deteriorate the production process of the MVA-LCD and result in a lower production yield.